There was a shocking result in the first part of our windscreen wiper motor test in BOOTE 02/205, when we took a close look at six models that are generally used on smaller pleasure craft;
The majority of the test specimens failed after a short period of use.
In practice, this can lead to an increased risk of accidents. If a windscreen wiper fails in the rain, for example, the helmsman may overlook a buoy or a transverse boat. It will therefore be interesting to see whether the motors for medium-sized and larger boats will show a similarly poor picture.
Once again, we were supported by the Department of Electrical Engineering and Information Technology at Darmstadt University of Applied Sciences under the direction of Prof Dr Thomas Betz. Measurements and analyses were carried out by Marcel Lutz, who was also involved in 2015.
The candidates
Even when unpacking, all the test candidates made a much better impression than when testing the smaller motors. The AFI 1000 came from Mastervolt and impressed with its clean workmanship and exemplary wiper arm.
Allpa sent three candidates into the race: the Bravo, the Charlie and the Echo, all of which made a solid first impression. However, the massive wiper arms were sharp-edged throughout.
Exalto supplied the 215 BD and the 233 BD. The 215 BD was already visually appealing with a very high-quality, excellently finished design housing. Problems only arose later due to unrecognisable design flaws. The 233 BD looks less tidy, but is also rock solid.
However, the colour designations of the cables in the instructions, which did not match the motor, led to assembly problems.
Talamex sent the Formar HD windscreen wiper motor, which also impressed with a rock-solid design housing with exemplary labelling of the connections. Observator delivered the beefy, extremely stable 30 Nm from Hepworth - the most powerful engine in the test. Roca entered the race with the W12, which already stood out visually with an excellently crafted housing with fine lines.
From Allroundmarin came the solid, but otherwise unremarkable TMC-00901/TMC-00902. The equally solid-looking, high-gloss lacquered Vetus RW-01A with its additional plastic housing was sent to us by Bukh Bremen. Windscreen wipers and wiper arms were selected and sent by the suppliers. The editorial team had no influence on this.
The test conditions
The tests were based on the findings from the first part.
As the ISO 17899 standard for wiper systems for ships requires extremely long tests that would have exceeded any time frame, practical considerations once again led to the definition of considerably easier test conditions, which are based on DIN standard 72781-2 "Wiper systems for road vehicles", among others.
The test stand already developed by the university for the first test with aluminium profiles, a glass pane inclined at 45 degrees, fixtures for the various motors and the measuring sensors as well as a standard-compliant sprinkler system with water collection basin was also used unchanged for the larger motors.
On the other hand, the measurement cycles changed, as the larger motors must also be assumed to be used somewhat differently and more intensively, particularly during wet running. Five cycles were tested, each with eight hours of wet running and one hour of dry running. One low-speed cycle was followed by one high-speed cycle. In total, the eleven test candidates spent 55 days on the test bench.
Between the cycles and at the end, it was again checked whether the axle and gear play or the contact pressure on the disc had changed. During the test runs, all measured values were logged at intervals of 20 milliseconds and flow charts were created to enable all processes to be analysed precisely.
The results
In contrast to the first part with the smaller engines, the tests with the "big brothers" went almost without a hitch. With just one exception, which resulted in a total failure, the motors all held up. The AFI 1000 from Mastervolt ran completely unobtrusively at moderate temperatures. When testing the maximum torque, the fuse even tripped - that's how you imagine it.
The Bravo, the Charlie and the Echo, Allpa's triumvirate, also performed their duties without any problems. However, the Bravo's high operating temperature was noticeable. The Echo was characterised by its quiet running.
Exalto unfortunately had the black sheep in the race with the 215 BD. "Unfortunately" because the motor looks extremely high-quality and actually is. However, there is a fatal design flaw that leads to overheating and the resulting failure.
The first test cycle ends after 137 minutes at 108 °C. A retest with a second unit leads to the same result. Although the replacement motor survived the first cycle, it failed in the second cycle after just 46 minutes at an impressive 120 °C. The heat damage is clearly recognisable on both models after opening. Heavy carbon abrasion is also noticeable. The high temperature development even leads to damage to the installation housing of the test stand. On a boat, the immediate surroundings would possibly be at risk from overheating damage.
An analysis during disassembly shows that the problem is caused by the cooling fins placed on the engine - actually a positive approach.
In the 215 BD, an additional casing has been installed for this purpose, which, however, has an air cushion between the actual motor housing and the cooling element. This air cushion acts as an insulator and prevents the dissipation of heat through the cooling fins instead of promoting it. The result: the motor overheats and burns out.
The Exalto 233 BD, on the other hand, ran smoothly, but was also notable for its high temperatures and rather loud wiper blades. The Formar HD windscreen wiper motor did its job completely unobtrusively and impressed with the lowest operating temperature of just 39.7 °C in the test. However, the windscreen wiper weakened in the penultimate pass. The last test cycle could no longer be carried out due to the breakage of the engagement function on the wiper arm, but this was not the fault of the engine itself. It was still in excellent condition after the tests.
The Observator 30 Nm from Hepworth was the most powerful of all the candidates. The engine itself ran completely unobtrusively, with only a loud wiper blade to be noted. The quiet Roca W12 also did its job without any faults. The same applies to the TMC-00901/TMC-00902 and the Vetus RW- 01A, whereby the latter had an above-average operating temperature of up to 73.1 °C.
The test conclusion
In contrast to the first part of the test with the small motors, the more powerful specimens show that it is indeed possible to manufacture reliable windscreen wiper motors, despite the higher requirements of 40 hours of wet running and five hours of dry running. Even with our new criteria, however, we are still far below the values specified by the standards.
All candidates presented themselves in a rock-solid manner and - with the exception described in detail above - passed the tests.
Even the "problem child" Exalto 215 BD is also characterised by a very high manufacturing quality. The design flaw that proved to be its undoing can certainly be corrected by the manufacturer.
The motors themselves generally ran quietly. In all cases, the sometimes noticeable increased noise was caused by the windscreen wipers themselves. In general, faults were more noticeable in the wiper arms and wiper blades, which can be replaced if necessary. This is probably recommended for the otherwise flawless Formar HD windscreen wiper motor, whose wipers were conspicuous due to a broken attachment.
